Nasdaq OMX Group in a press release said the index will undergo a “special rebalance” prior to the market’s open on May 2. The rebalancing will not change the methodology used to calculate the Nasdaq-100 Index or the benchmark securities, the company said.

The change “reflects our commitment to ensure the Nasdaq-100 Index remains a relevant benchmark for investors around the world who track the performance of the U.S. equity market,” said John Jacobs, executive vice president at Nasdaq OMX Global Index Group. The benchmark will remain “an objective, transparent, rules-based index,” he said in the release.

For every $1 billion benchmarked to the Nasdaq-100, an estimated 9.5 million shares will trade, according to the presentation. The rebalancing will be felt in markets as passive managers buy and sell stocks to reflect the new weightings. Apple shares in particular should see selling pressure due to the company’s expected dramatic reduction in the Nasdaq-100.

“It’s going to be a big trade,” Nasdaq’s Jacobs told the WSJ. However, “we wanted to make this very transparent. Everyone will see what we’re doing and everyone will have a month before we do this,” he told the newspaper.

PowerShares QQQ is up about 5% so far this year.

The opinions and forecasts expressed herein are solely those of John Spence, and may not actually come to pass. Information on this site should not be used or construed as an offer to sell, a solicitation of an offer to buy, or a recommendation for any product.